<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        #star{
            width: 0px;
            height: 0px;
            border-bottom: 70px solid red;
            border-left: 100px solid transparent;
            border-right: 100px solid transparent;
            margin:150px auto;
            transform: rotate(35deg);
            position: relative;
        }

        #star::before{
            content: '';
            width: 0;
            height: 0;
            border-bottom: 80px solid red;
            border-left: 30px solid transparent;
            border-right: 30px solid transparent;
            position: absolute;
            transform: rotate(-35deg);
            top:-45px;
            left:-65px;
        }
        #star::after{
            content: '';
            position: absolute;
            border-bottom: 70px solid red;
            border-left:100px solid transparent;
            border-right: 100px solid transparent;
            transform: rotate(-70deg);
            top: 3px;
            left:-105px
        }

        #star1{
            width: 0px;
            height: 0px;
            border-bottom: 100px solid red;
            border-left: 50px solid transparent;
            border-right: 50px solid transparent;
            margin: 100px auto;
            position: relative;
        }

        #star1::after{
            content: '';
            width: 0px;
            height: 0px;
            border-top: 100px solid red;
            border-left: 50px solid transparent;
            border-right: 50px solid transparent;
            position: absolute;
            top:30px;
            left: -50px;
        }

    </style>
</head>
<body>
  <div id="star"></div>

  <div id="star1"></div>
</body>
</html>